Apparatus and article for polishing gemstones

ABSTRACT

Disclosed is an apparatus for working gemstones. The apparatus comprises an abrading article and a rotatable support with a guiding feature for holding and rotating the article. The abrading article has a mounting bore substantially larger than the guiding feature. A balancing arrangement facilitates balancing of the article, and an abrading article removal tool is operative to remove the abrading article from the rotatable support.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Israeli Patent Application No. 168588, filed on May 15, 2005, which is incorporated in its entirety herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The apparatus and article relate to the field of gemstone working.

2. Description of the Related Art

Grinding and polishing are the most common gemstone working (shaping) operations. Gemstones can be worked in different ways. Most commonly, gemstones are polished or worked mechanically on a fast rotating, metal working member or scaife. A scaife is a heavy, cast iron, horizontally spinning wheel. The working surface of the scaife is impregnated with oil and diamond powder. The term “working” in the context of the present invention includes polishing and grinding of gemstones and other precious and semi-precious stones.

For gemstone working purposes, the gemstone is mounted on a dop held by a tang and leveled with respect to the working member. The gemstone leveling procedure provides for the correct angles and correct size of the facets. The term gemstone includes diamonds, and other precious and semi-precious stones. As the number of diamonds polished on the same scaife increases, the diamond impregnated surface of the scaife wears out and the scaife has to be renewed. Renewal of the scaife changes the scaife dimensions. Following renewal, the scaife has to be balanced once again and the gemstone also has to be leveled again.

Israeli Patent Application No. 162,502 to the same Assignee teaches a method of working gemstones enabling rapid gemstone working member exchange and gemstone processing sequence continuation without the need to level the gemstone or the working member. The operation of the working member may present some difficulties related to working member mounting and exchange. The present apparatus and replaceable abrading article are resolving this problem.

SUMMARY OF THE INVENTION

According to one aspect of an embodiment of the invention, an apparatus for working gemstones, is disclosed. The apparatus comprises an abrading article having a mounting bore therein, and a rotatable support having a guiding feature that holds and rotates the article. The diameter of the mounting bore may be substantially larger than said guiding feature. The apparatus also may include a balancing arrangement for balancing said article upon said support. The apparatus may further include an abrading article removal tool for removing said abrading article from said rotatable support.

According to another aspect of an embodiment of the invention, A disk like abrading article having a mounting bore, is disclosed. The article may comprise two flat parallel surfaces, wherein one of the surfaces may have a coating of diamond powder, and wherein the diameter of the bore may be substantially larger than the diameter of a corresponding guiding feature.

According to a still further aspect of an embodiment of the invention, a method of mounting and exchanging abrading article on a rotatable support of a gemstone working apparatus is disclosed. The method may typically comprise mounting the abrading article on the support and balancing the article by sliding it in a proper position on the support. The method may also include polishing at least one facet on said article and exchanging the article.

BRIEF DESCRIPTION OF DRAWINGS

The features and advantages of the apparatus and the article associated with its use will be apparent from the more detailed description. The exemplary embodiments of the apparatus are illustrated in the accompanying drawings in which like reference numbers refer to the same parts throughout the different figures. The drawings are not necessarily to scale. Emphasis is placed upon illustrating the principles of the apparatus.

FIG. 1 illustrates some elements of an exemplary embodiment of a gemstone working apparatus;

FIG. 2 is an expanded view of some elements of an exemplary embodiment of a gemstone working apparatus;

FIG. 3 is a schematic illustrations of an exemplary embodiment of the rotatable support of the apparatus shown in FIG. 2;

FIGS. 4A and 4B are schematic illustrations of exemplary embodiments of the abrading article of the apparatus shown in FIG. 2;

FIGS. 5A and 5B are expanded views illustrating the operation of the balancing arrangement of the apparatus shown in FIG. 2;

FIG. 6 is an expanded view illustrating the balancing arrangement operation of the apparatus shown in FIG. 2 for balancing an article without a mounting bore;

FIGS. 7A and 7B are expanded views illustrating the operation of the abrading article removal tool of the apparatus shown in FIG. 2;

FIGS. 8A and 8B are schematic illustrations of another embodiment of a gemstone working apparatus illustrating operation of the balancing arrangement and abrading article removal tool, wherein FIG. 8A is a side view of FIG. 8B; and

FIG. 9 illustrates some elements of an exemplary embodiment of gemstone working apparatus implemented on an existing gemstone working machine.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIG. 1 illustrates some elements of an exemplary embodiment of a gemstone working apparatus. Gemstone working apparatus 100 includes a rotatable support 104; a removable (replaceable) and disposable gemstone abrading article 108, a balancing arrangement 110 and abrading article removal tool kit 112. Electrical or pneumatic motor 114 rotates support 104 with abrading article 108 mounted on it. Motor 114 and support 104 are permanently mounted in a table type frame 116 having a flat tabletop surface 120. Rotatable support 104 provides a support surface 130 on which removable and disposable abrading article 108 rests by its lower surface 154. A guiding feature 162 facilitates the mounting of article 108. Arrows 134 indicate the mounting direction of abrading article 108 to support 104. Rotatable support 104 possesses retention forces that hold article 108 when support 104 rotates. Balancing arrangement 110 is mounted as removable or fixed to tabletop surface 120. For article 108, removal abrading article removal tool 112 may be mounted on tabletop surface 120. Otherwise, tool 112 is located in an enclosure within frame 116 or in an easy accessible location outside frame 116. Also shown in FIG. 1 are gemstone 124 and a gemstone holding and leveling means such as a dop 126 that may be held by a tang (not shown). Gemstone 124 has to be worked on apparatus 100.

FIG. 2 is an expanded view of the same elements of the exemplary embodiment of gemstone working apparatus. The elements and their possible relative positions are shown for illustrative purposes only.

FIG. 3 illustrates an exemplary rotatable support 104 having permanent magnets or electro-magnetic inserts 144. There is no direct contact between permanent magnet inserts 144 and any of the surfaces of abrading article 108. Magnetic inserts 144 generate an abrading article retention force that holds article 108 (FIG. 1) on support 104. Inserts 144 are inserted in troughs made in body 150 of rotatable support 104. A layer of material exists between magnetic inserts 144 and lower surface 154 (FIG. 1) of abrading article 108. This method of insertion of permanent magnets provides a single material structure to surface 130, which may be thus manufactured with greater accuracy and at a lower expense. Surface 130 of rotatable support 104 which is in contact with lower surface 154 of abrading article 108, has an external diameter smaller than the rest of the body of support 104 and smaller than the diameter of articles 108 and 180 (FIG. 4). Generally, support 104 may be implemented as a cylindrical or other shape body of smaller than article 108 diameter. Not all of the lower surface of the abrading article is in contact with the respective surface of the rotatable support. Rotatable support 104 has guiding feature 162 that facilitates mounting of abrading article 108 on rotatable support 104. Bore 166 enables connection of support 104 to motor 114 to which it may be fastened by screw 128 or any other suitable fastening means.

Use of permanent magnets or electromagnets necessitates use of ferromagnetic material for the abrading article. For other types of retention mechanisms, such as vacuum, the abrading article may be made of a non-magnetic material. Vacuum orifices may be inserted or drilled in the rotatable support and a vacuum pump may provide vacuum through a rotary joint. In this case atmospheric pressure would retain the abrading article on a rotatable support.

Abrading articles (FIG. 4) may have different shapes, although the simplest shape of the abrading article is a disk-like shape. Surface 154 is a flat surface (FIG. 4A). Abrading article rests with it on flat surface 130 (FIG. 3) of rotatable support 104. The abrading article has a flat diamond powder coated working surface 184. Surface 154 and surface 184 are parallel to each other. The diamond powder may be of a single grade. Alternatively, sections of the abrading article may be coated by different grades of diamond powder. Different abrading articles may be coated by diamond powder of different grades.

Abrading article 108 would have a thickness smaller than has rotatable support 104. Rotatable support 104 provides the necessary stiffness keeping working surface 184 flat when working a gemstone. All of the removable articles are substantially of the same thickness. Their exchange does not change the working plane position. Accordingly, the exchange of the abrading article does not create the need to level the gemstone being worked or the working member.

Abrading article 108 (FIG. 4A) has mounting bore 186, which facilitates mounting to rotatable support 104 (FIG. 3). For mounting, article 108 is threaded through bore 186 on guiding feature 162 of rotatable support 104. When coupled with a tight fit guiding feature helps to locate article 108 such that the rotation axes of the article and rotatable support 104 coincide or are close to each other. Following this, in conventional machines the rotating support with the abrading article are balanced by adding balancing masses/weights to the assembly. Retention forces developed by electro-magnets or vacuum may be switched ON and OFF making the mounting of article 108 with guiding feature 162 of rotatable support 104 easy, regardless of the clearance of the respective surfaces. Permanent magnets, which are the simplest retention means, cannot be switched ON and OFF and the permanent forces they develop make mounting of article 108 with guiding feature 162 of rotatable support 104 less convenient.

In one embodiment (FIG. 4A), abrading article 108 has a diameter of mounting bore 186 substantially larger than the diameter of guiding feature 162 of rotatable support 104. In another embodiment (FIG. 4B), abrading article 180 has no mounting bore at all. It is a flat round disk.

FIGS. 5A and 5B illustrate the operation of the balancing arrangement. Arrangement 110 (FIG. 1) includes a stand 188 and an adjustment screw 190. Stand 188 may be removable or permanently attached to tabletop surface 120 by any suitable mechanism. Adjustment screw 190 is positioned such that it may apply pressure to abrading article 108. Article 108 has a diameter of mounting bore 186 substantially larger than the diameter of guiding feature 162 of support 104. Support 104 may now be rotated and screw 190 advanced until it touches article 108 at a point on its diameter that has maximal run-out (FIG. 5B). Advance of screw 190 applies pressure to article 108 and displaces it on surface 130 of support 104. The displacement is possible since mounting bore 186 has a diameter substantially larger than the diameter of guiding feature 162. Article 108 actually slides or moves towards the center of rotation of support 104. The operation continues until support 104 with mounted on it article 108 are balanced. The balancing is performed without adding to the rotating mass unbalance compensation masses. Article 108 slides on surface 130 until its center of mass comes to a position that balances the coupled rotating masses of rotatable support 104 and article 108. The thread pitch of screw 190 may be selected such as to ensure proper balancing accuracy. The balancing accuracy may be controlled by any available balance control instrument. Tip 194 of screw 190 may be adapted to have minimal friction with the outer surface of article 108. FIG. 5B shows the final balanced position of article 108. After this, screw 190 is retracted, the gemstone is leveled and the gemstone-working operation may begin.

FIG. 6 shows the balancing procedure for article 180 that has no mounting bore. Accordingly, rotatable support 196 has no guiding feature, although it may have a type of security lock to hold the article in case of emergency.

As disclosed above, the abrading article is exchanged when it becomes unusable. Exchange of article 108 or 180 may be performed by pulling it off support 104 or 196. When electro-magnets or vacuum are used as a retention mechanism, they may be simply switched OFF. Pulling article 108 or 180 off the surface of support 104 (196) that has permanent magnet inserts may require a force substantially larger than sliding article 108 or 180 on the surface of support 104 or 196 and may not be convenient for manual operation. FIGS. 7A and 7B illustrate the operation of abrading article removal tool. Tool 112 includes stand 200 having a thread and engaging bushing 204, that has an internal thread. Tool 112 further includes an eccentric rotatable bushing 206, a cylindrical bushing 208 and a flat member 210. Insert 216 has a similar thread to stand 200 and may be inserted into tabletop surface 120 of frame 160. Alternatively, a thread may be made in the tabletop part of frame 160.

For removal of articles 108 or 180, stand 200 is engaged with insert 216 such that eccentric rotatable bushing 206, may be rotated to enter the groove formed by the section of support 104 that has a smaller diameter than the rest of support 104 and lower than the surface of article 108 (180). Cylindrical bushing 208 has a thickness about the thickness of article 108 (180) and overlays bushing 206. Flat member 210 is placed on the top of it. Flat member 210 is rotated such that its longer part is over article 104 or 180. The assembly of the above mentioned parts is fastened together by nut 214 or any other fastening means. Threaded stand 200 is rotated such that it disengages threaded insert 216 or tabletop surface 120 (FIG. 8). The disengagement movement of stand 200 (FIG. 7B) moves bushings 206, 208 and flat member 210 as shown in FIG. 7B and pulls article 108 (180) from support 104.

There is a variety of constructions for gemstone working apparatuses. Apparatus 100 (FIG. 2) has abrading member working surface 184 (FIG. 4) above the level of tabletop surface 120 (FIG. 2) on which the dop is held in place by a tang movement. FIG. 8 shows a gemstone working apparatus where abrading article working surface 184 is at the level of tabletop surface 120. Balancing arrangement 110 and abrading article removal tool 112, as FIG. 8 shows, are adapted to this architecture. Adjustment screw 190 pushes/pulls a pin that moves in a groove 224 and is in contact with article 108. Abrading article removal tool 112 has an anchored screw 228 that engages article 108 and pulls it from support 104 in a mode similar to the above description. FIG. 8 illustrates a cylindrical shape support having an external diameter smaller than article 108.

The elements of the apparatus and the method of exchanging an abrading article may be adapted for use in existing conventional gemstone working machines. FIG. 9 illustrates a conventional gemstone working machine 240 with balancing arrangement 110 and abrading article removal tool 112 assembled on it. FIG. 9 shows an additional exemplary form of rotatable support 244 having a form similar to the existing working members (scaife) with removable abrading article 108 mounted on it. Support 244 has permanent magnetic inserts that provide the article holding force. The exemplary form of rotatable support 244, similar to the conventional working member, was selected for demonstration purposes only. As shown, other forms and shapes of the rotatable support are possible.

As the number of gemstones polished on the same working surface of an abrading article increases, the diamond-coated surface of the article wears out or becomes unusable. By utilizing the present apparatus and article exchange method, it is easy to remove the article and mount a new abrading article when necessary. It is easy to balance the new abrading article using the balancing arrangement.

While the apparatus and the article have been described in detail, it should be understood that various changes, substitutions and alterations could be made hereto without departing from the spirit and scope of the specifications as defined by the appended claims. 

1. An apparatus for working gemstones, comprising: a) an abrading article having a mounting bore therein; b) a rotatable support having a guiding feature, wherein said support holds and rotates said article, wherein the diameter of the mounting bore is substantially larger than said guiding feature; c) a balancing arrangement for balancing said article upon said support; and d) an abrading article removal tool for removing said abrading article from said rotatable support.
 2. The apparatus of claim 1, wherein said article is held against a force selected from the group consisting of magnetic forces, electromagnetic forces, and atmospheric pressure forces.
 3. The apparatus of claim 1, wherein said balancing arrangement is removably mounted on said apparatus.
 4. The apparatus of claim 1, wherein said balancing arrangement is fixedly mounted on said apparatus.
 5. The apparatus of claim 1, wherein said balancing arrangement provides said article with sliding movement on a surface of said rotatable support.
 6. The apparatus of claim 1, wherein said balancing of the article and support is achieved without the addition of balancing masses.
 7. The apparatus of claim 1, wherein said abrading article removal tool removes said article from said support.
 8. The apparatus of claim 1, wherein said abrading article has a diamond coated working surface.
 9. A disk like abrading article having a mounting bore, wherein the article comprises two flat parallel surfaces, wherein one of said surfaces is diamond powder coated, wherein the diameter of said bore is substantially larger than the diameter of a corresponding guiding feature.
 10. The article claim 9, wherein said article diameter is larger than the diameter of the surface on which it rests.
 11. The article claim 9, wherein said diamond powder is a single grade powder.
 12. The article claim 9, wherein said diamond powder is of different grades.
 13. A method of balancing a working member having a rotatable support and an abrading article, comprising repositioning the article on the rotatable support without using additional balancing masses for balancing the working member.
 14. An apparatus for working gemstones, comprising: a) an abrading article; b) a rotatable support possessing retention forces; c) a balancing arrangement for balancing said article; and d) an abrading article removal tool for removing said article from said rotatable support.
 15. The apparatus of claim 14, wherein said abrading article has no mounting bore.
 16. A method of mounting and exchanging abrading article on a rotatable support of a gemstone working apparatus, comprising a) mounting the abrading article on the support; b) balancing the article by sliding it in a proper position on the support; c) polishing at least one facet on said article; and d) exchanging said article.
 17. A tool for removing an abrading article held on a support by permanent magnetic forces, wherein said tool pulls said article from said support.
 18. An apparatus for working gemstones, comprising: a) an abrading article; b) a rotatable support having a guiding feature for guiding said article, wherein the abrading article has a mounting bore substantially larger than said guiding feature.
 19. The apparatus of claim 18, wherein said article is held by forces that are magnetic, electromagnetic or by atmospheric pressure.
 20. The apparatus of claim 18, comprising a balancing arrangement for balancing said article.
 21. The apparatus of claim 18, further comprising an abrading article removal tool for removing said abrading article from said rotatable support.
 22. A disk like abrading article, comprising two flat parallel surfaces, wherein one of said surfaces is coated with diamond powder, wherein the diameter of said article is larger than the diameter of a surface on which it rests.
 23. The article of claim 22, wherein said diamond powder is a single grade powder.
 24. The article of claim 22, wherein said diamond powder is of different grades.
 25. A rotatable support for holding an abrading article, wherein said support has a flat surface for resting said article thereupon, wherein said support has a diameter smaller than said article. 